Shared-radius co-prime circular array improves 2D direction finding accuracy
Hybrid Continuous DoA Estimation with Shared-Radius Co-Prime Circular Arrays
Information TheoryNetworking and Internet Architecture
Summary
Finding where a signal comes from in 3D space using antennas can be tricky and sometimes inaccurate. This paper shows a new type of antenna setup that uses two circular groups of antennas with specially chosen sizes. The method helps pinpoint signals more accurately and avoids some common errors, working well even when signals are weak or noisy. The approach combines a quick rough estimate with a smart continuous way to refine the direction measurement.
What this means in practice
- •For wireless communication engineers: Enhance antenna designs for improved 3D signal direction detection in multi-antenna systems.
- •For radar system developers: Improve target localization accuracy using a low-complexity array structure with reduced interference effects.
Authors
Keyvan Aghababaiyan
Abstract
This paper proposes a shared-radius co-prime circular array for high-resolution, continuous 2D Direction-of-Arrival (DoA) estimation in 3D space, jointly estimating azimuth and elevation angles. The proposed architecture consists of two uniform circular sub-arrays with co-prime antenna counts sharing a common radius RR, a design that intrinsically suppresses mutual coupling leakage compared to dense uniform arrays. Unlike existing works that rely on complex phase-mode transformations to map circular structures to virtual linear arrays, we introduce a hybrid continuous-recovery framework operating directly in the physical spatial domain. By integrating a fast, discrete coarse-grid search with a swarm-intelligence continuous refinement stage, the proposed method completely bypasses discrete grid-mismatch limitations and computationally expensive eigenvalue decompositions. A rigorous theoretical analysis using Nivens Theorem establishes the spatial uniqueness of the true source direction, effectively resolving phase ambiguities. Simulation results demonstrate that this hybrid scheme achieves superior resolution and lower Root Mean Square Error (RMSE) at low Signal-to-Noise Ratios (SNR) compared to uniform configurations, while asymptotically converging to the theoretical Cramer-Rao Bound (CRB) at high SNRs.